Pressure-filter.



E- J SWBETLAND. PRESSURE FILTER,

, A 929,636I v PPLIoATroN FILED fm1, 1909' Patented July 27, 1909.

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E. J. SWEETLAND.

PRESSURE FILTER.

APPLICATION FILED H1351, 1909.

Patented July 27, 1909.

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E. J. SWEETLAND.

PRESSURE FILTER.

v APPLICATION FILED FEB. 1,1909. 929,636. Patented July 27, 1909.

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"muy I lullllllll UNI I!" imnmummm l ZUBJ. jf-20131223# ERNEST J. SWEETLAND, OF LOS ANGELES, CALIFORNIA.

PRESSURE-FILTER.

Specification of Letters Patent.

Patented July 27, 1909.

Application filed February 1, 1909. Serial No. 475,509.

' semi-solid material de osited upon the filtering medium while ii tration is in progress.

The object of this invention is to filter or clarify on a large scale liquids carrying solid matter in suspension.

A particular object 0f this invention is to provide a special meansof discharging the accumulated solid matter from the filtering surfaces without hand labor, and without the necessity of separating the units of the machine, as is customary with ordinary filter presses.

A further object is to construct a pressure filter, which is much lighter in Weight than filter presses `which have iron plates between the frames.

A further object is to provide a pressure filter that is free from moving parts.

A further object is to provide a pressure filter so arranged that the thickness of the deposited cakes of residue upon the filtering surfaces may be adjusted according to the permeability of the residue, so that if the residue o'i'iers a high resistance to the passage of liquids a correspondingly thin deposit may be formed upon the filtering surfaces, but in cases vrherc the residue is of a porous nature, a correspondingly thick deposit may be formed before discharging the contents of the filter.

In ordinary filter presses a thin deposit of residue may be made on the filtering cloths, if desired, butthe labor of removing such a deposit from the filter cloth is so great that 'it is not economical to operate such filter )resses unless the'v chambers between the iilter cloths are sufficiently filled to form a compact cake.

A further object is to provide a filter press with a continuous unobstructed passageway along the bottom thereof that is 1n full communication with thek filter devices and into which the residue may be dropped from the lter devices, and subsequently sluiced therefrom by the passage of a current of Water therethrough.

A further object is to provide a pressure filter wherein unfilterable residue may be discharged by first causing it to fall from the filter devices into an open space below the filter devices, from uhich open space it is removed by means of a current of liquid.

A further object is to provide a )ressure filter with suitable connections to tIhe filter devices therein, which permit of the filter devices being placed incommunication with any one of several conduits at the will of the operator.

A further object is to provide a frame for pressure filters, or filter presses, having a cross section substantially as shown, Whereby great strength is given the frame, while the weight is reduced to a minimum.

ln the'comnion types of filter presses, the solid matter from the liquid being filtered, is deposited in a series of chambers between rigidavalls of filtering fabric and the result is that the solid `matter so packed under pressure, offers a high resistance to the passage of a liquid through it, but in the invention herein described no such packing occurs, and consequently the deposited solid matter is more readily Washed free from any Vsoluble matter it may be desirable to recover therefrom, and furthermore, the solid matter not being packed in the form of a hard calie in my device, it is more easily removed by means of Water under pressure, for the nature of the cake of residue is such that it readily disintegrates when a stream of liquid is brought to bear upon it. This feature will best be understood by referring to any ordinary type of filter press, Which is built up of a series of corrugated plates and open frames or containers Vplaced between the plates, and the filtering canvas placed over the faces of the plates in such a manner that when the press is assembled for use a series of cells with rigid canvas-covered walls is formed.

When a liquid containing solid matter is filtered in thesecells under pressure, it is found that th'e cakes formed in such presses are very compact, for the reason that the size of the cake of residuum is limited'to the size of the cell, and as the cake has no room to expand it necessarily becomes .harder and harder as moresolid matteris forced in; While in my press it will be seen that the Whole interior of the machine is practically a continuous chamber Without partitions, and filter devices, as shown, each of which is a unit in itself, are placed in the upper part of the chamber, and have sufficient space between them to allow the deposited solid matter to build upo'n their surface without the cake being restricted as to 'shape or size. The deposited cali'es are never allowed to become so thick that those in one frame come in contact with those in the adjacent frame, an open space always being left between them, which leaves the 'cake of deposited unilterable matter free to fall to the open space below, when it is desired to discharge the cakes of residual unfilterable matter.

It is thc intention of the inventor that the present application shall vcooperate with Patents Nos. 885,398 and 887 ,285, both of which were issued to the present applicant.

A particular use of the invention described, is in the filtration of finely divided ores from cyanid solution in the cyanid process of goldextraction; and in the manufacture of sugar from su ar beets.

The invention will e more clearly under- .stood by reference to the accompanying' drawings, of which- Figure 1 is a side elevation of the pressure filter assembled, with portions broken away to better illustrate the interior construction.

`upon the tie rods 5.

Fig. 2 is an end elevation of one of the frames, or units, ofwhich the filter is constructed7 showing the filter devices in place in the upper part of the frame and the open space below them. Fig.3 is a detailed elevation ofy one of the filter devices removed-from'the frame with a portion of the filtering medium broken away to show the interior construction. Fig. 4 is a vertical section on the line 4--4 of Fig. 3. Fig. 5 is the clip, Vby means of which the filtering fabric is held at the bottom of the filter device. Fig. 6y is a cross section of the frame on the line l6*--6 of Fig. 2. Fig. 7 is a cross section on the line 7-7 of Fig. 2. Fig. 8 is an end elevation of Vone of the frames, or units, with a modified forin of filter devices oftubulai' form shown therein, the upper portion of some of the devices being broken away to show the spray pipe. Fig. 9 is a sectional view on the line 9 9 of Fig. 8. Fig. 1() shows one of the tubular filter devices removed with sections broken away to show the interior construction.

Referring more particularly to the parts with special reference to Fig. 1, l. and 2 are the main standards which support the body of theinachine. The main body of the niachine is built up of a series of frames 3, which are provided with the rollers 4, which rest The head 6 forms a closure for the upper end of the series of frames and is held by the nuts 7 upon the tie rods 5. 8 is another head, which forms a closure for the series of frames at the lower end. There is a pressure screw 10, which is operated by a lever inserted in the wheel 11; by means of this screw a high pressure is brought to bear against the head 8. The head 8 is provided withy rollers 9, which allow it to .I nove upon the tie rods 5 when the screw 1() 1 s advanced or withdrawn. Each frame 3 1s provided with a gasket 12 set in a groove around the fr hen the head 8 is tightly l built up of a series of sections to promo'jte accessibility to the interior thereof. l

The whole machine is assembled in such a manner that theiilter devices hang vertically, while the chamber is higher at one end than the other in order to promote drainage.

In a pressure filter where a large volume of liquid is to be handled it is desirable to have the frame oflarge area, and one of the special features of my invention is the method of constructing the frames t0 give the maxi- Vmimi strength with the minimum weight.

This construction is adaptable to almost any type of sectional pressure filter.

Reference to the sectional portion of Fig. 1

clearly shows the shape of the cross section 'of vthe frame, where it will be seen that the cross section somewhat resembles an ordi-` v nary railroad rail, the web`13 uniting the bulb 14 to the main inner portion of the frame 1,5." I have found by actual tests 4that a frame so constructed will resist a much higher pressure than the same Weight of metal distributed in the manner customary A for filter press frames.

To the movable head 8 is attached a hopper 16 to 'which are connected the valvesA v17 and 18.

A launder 19 is .provided to carry away residues discharged through the valve 18. i

Each frame carries4 a series of filter devices 20`which are suspended from the top of the I pro vided for the passage of the same.

22 is a perforated pipe which passes along the top of the frame mid-Way between the rows of filter devices in the several frames. This pipe I term a spray pipe, and its use is to project a spray of liquid upon the filter devices 20. This pipe is more clearly shown in Fig. 8.

A pipe connection 23 and the valve 24 are screwed into an opening in the bottom of the The main object being to head 6. and on the inside of the same head is screwed the nozzle 25, in such a manner that when a liquid is projected through it it sweeps along through the space 26 below the filter devices and .finally out through the valve 18.

No. 27 is a valved pipe connection, which communicates with the interior of the filtering chamber and serves either as an outlet or inlet for air, while the chamber is being filled or emptied of liquid.

ln Fig. 2, the details of cach frame, or unit, are more clearly shown, referring to saine, 2S, 29 and 4`3() are openings or conduits through the frame and are each provided with a groove 31 for a gasket. When the gaskets are in place and the series of frames clamped together, these conduits forni continuous openings through the entire length of the filter.

A suitable pipe connection 32 connects conduit 21, which runs from one side of the frame to the other, with a three-way valve 3S, so that the interior of the filter devices 20 may be placed in communication with either the conduit 28 or 29 at the will of the operator. These conduits terminate at the end ol' the filter in the pipe connections 28A and 29A. By means of the pipe connection 34 and the valve 35, the perforated spray pipes 22 are brought into communication with the conduit 30.

By a study of the foregoing arrangements, it will be understood that if a pressure of liquid is maintained in the conduit 30, the liquid may be projected through all of the spray pipes 22 simultaneously, or by means of the valves 35 the spray may be projected through any individual spray pipe, or any number of spray pipes, as may be desired by the operator. The advantage of this arrangement is that if but a small volume of water under pressure is available, the entire pressure may be concentrated in one spray pipe, at a time, and thus the maximum elliciencj,r and cleaning power obtained from it.

v''hen in operation, the clear filtrate passes through the pipe 32 into the conduit 29, and the cock 36 is provided to enable the operator to obtain samples of 'filtrate from each unit when desired, and if a leak in the filtering medium should occur at any time, the operator can easily determine which unit contains the leak by taking samples l'roni these cocks.

Referring to Fig. S, each filter device 20 is provided with the perforated pipes 37', which are attached to a corrugated board 38 by means of the bands 3Q. A teo 4() unites the two pieces of pipe 37 and into this tee is screwed the nipple 41, which is provided with a continuous thread over its entire length. A lock nut 42 is screwed on this ting or bui-lap.

of heavy canvas 43. A hole is cut through this canvas at the point 44 just large enough to admit the nipple 41 to pass through it. In practice the filtering canvas is sewed along the edges 45, which makes it in the form' of a bag with the edge 46 left open.'

The hole 44 is then cut and the whole interior portion slip )ed into the bag and the lock nut 42 tig itly screwed down, which makes a tight joint around the canvas. If desired, the canvas may be reinforced at this point, or a Washer may be placed under the ock nut to insure a tight joint.l 'llie open end of the bag is then closed by the clip 47, shown in detail in Fig. 5, which makes the filtering surface intact, so that it is impossible for any liquid to finally get into the conduit 21 without first passing through the filtering canvas when the 'filter devicesare screwed tightly in place, as shown in Fig. 2. The nipple 41 has connection with the conduit 21 through a series of holes 4S which are tapped into the conduit. Clip 47 is coinprised of two arms 49 and 50 rovidcd with a pivot 51 at one end, and the ink 52 at the other, which holds them together when applied to the open end of the canvas bag. These clips are' preferably applied by first rolling the canvas once or twice around one of the arms and then springing the other one into position and applying the link 52.

ln the modification shown in Fig. 8, the construction of the frame is essentiallythe saine as Fig. 2, with the exception that the filter devices 20 are tubular in form instead of being flat. Each filter device is assembled and screwed into the threaded openings 48 in the same manner as were the Il at filter devices in Fig. 2. The spray pipe 22 is clearly sho`wn in this iigure, and in this niodification, as well as in the arrangement shown in the other figures, tl'e adhering resi due, or unfilterable matter may be washed from the exterior of the iilte'r devices by means of projecting a spray upon their exterior. lt will be understood that with both arrangements, the removal of the solid iiiat ter is assisted by the application of pressure to the interior of the filter devices preferably `applied while the spray pipes are in action.

Referring to Fig. 10, each tubular filter device comprises an inner'member of perfoi-ated pipe 53, the lower end of which is closed by the plug- 54. Around this pipe, a layer of any convenient porous material may be placed, such as wire screen, cocoa mat- I prefer to use cocoa niatting, as shown 55. The outer cover, or bag, of canvas 56 incleses the entire interior portion and is held in place by the clip 57. A reducer 5S) is screwed to the pipe and this reducer in turn screws into the openings 48.

The method of operating is as follows: The liquid to be ilter'ed may be brought into the mainchamber of the lter through any convenient o ening, but I prefer to enter the liquid throng the valve 17. While the chamber yis filling, the vent 27 is open to allow the vinclosed air to escape. As soon as the chamber is full the vent 27 is closed and as the liquid continues to enter under pressure it is forced through the canvas of the filter devices 20, follows the corrugations in the board 38 into the perforated pipes 37, out through the nipple 4.1, into the conduit 21,'through the pipes 32 and valve 83 and canvas of the filter devices 2 0, and since the pressure throughout the entire chamber, from one end to the other, is equal, it follows that filtration is even and the cakes build up of uniform thickness.

.In practice the frames are about five inches wide and rows of filter devices are therefore this distance between centers.A

If the solid matter, contained in the liquid being filtered, is of a porous nature the cakes of residuum may be deposited about 2 inthickness, but if the residuum is of such a nature as to ofler a high resistance to filtration, Ithe thickness of the cakes may be varied accordingly. i

vInl the treatment of finely divided ore, oalledslimes in the cyanid process, it is desirable after the cakes have been -deposited to wash out any soluble material that may remain in them, and to accomplish this obect, after a cake of convenient thickness has een deposited, the pressure in the chamber is allowed to subside and at the same time a partial vacuum is brought to bear within the conduit 29 by means of a pump, (not shown in thedrawings) which is `directly connected with they ipe 29A. The object` of this vacuum is to old the cakes in place when they have been .relieved of pressure upon their outer surface, for if a cake of very great thickness has been deposited, it'would fall from the filter devices by its own gravity il'- left for any considerable length of time, but I have found that a vacuum of about 5 will hold the cakes in place for any reasonable length of time. Having connected the par- .tial vacuum with the conduit 29, which is now in communication with the interior of all of thefilter devices, 'the vent 27- is o ened and the contents of the chamber are rained to any convenientreceptacle through the valve 18.

ottom of the chamber (which in ordinary practice is not likely to occur), it

If durin filtration, any sediment has y settled in the may be removed -by a stream of li uid proj ected through the nozzle 25, while t e valve 18 is still open. The entire liquid contents of the filtering. tank, or chamber, have now been removed with the exception of such unfilterable matter as is clinging to the sides of thelilter devices. If it is desirable to partially dry the cakes, or treat them in place by passing air or any other gas through them, it may be done at this stage by simply introducing such gas into th'e chamber under pressure as it is desired to treat the contents with. The next step is to wash the adhering cakes of residue to remove any soluble matter contained therein, and to accomplish this, I introduce the liquid, with which the cakes are to be washed, through the valve 17 again allowing the inclosed air to escape through the vent l27. As soon as the chamber is filled with the washing liquid, the vacuum, which is applied through the conduit 29, is discontinued, as the pressure of the wash liquid upon the exterior of the cakes is sufficient to hold them in place. The wash liquid percolates through the cake and finds its way into the conduit 29, the same as did the filtrate. The washing is continued until the soluble matter is removed from the cakes. When this is accomplished, thewashing fluidin the chamber is returned to a convenient receptacle to be used over again.

It is obvious that the filter herein de,- scribed may be used for filtering valuable solid matter from liquids, in cases Where the solids are to be retained and the li uids rejected. For suoli service my filter o ers two particular advantages. First, the cakes of adhering solid matter may be removed from the filter surfaces without opening the filter, as often as may be desired, and consequently,

filtration is not retarded by a deposit upon the filtering surfaces. In this case the solid mattei' is allowed to remain in the `space .26 to be removed when convenient. Second, the space 26 lforinsa storage chamber for accumulated'solid mattei' where it may remain without interference to filtration until it is desired to recover it. For instance, in

the filtration of gold-'zinc' slimes when zinc precipitation is used in the cyanid process, the gold- Zinc product may be retained 1n the filter without danger of loss or inconvenience until time for a general clean-up. For such service the space 26y may be made as large as necessary to hold the accumulated product for any desired period.

Discharging the. residues- The Washed residues now in place clinging to the filter devices vare to be discharged. This may be accomplished by two entirely different methods with the same construction. 'Ihe methods will be described separately.

Method N o. 1: When the filter is installed,

which connects it with a convenient source a pipe is connected with the conduit 30, I

of water supply under pressure, so that whenever the valves 35 are opened a plurality of jets or streams of Water are projected upon the filter devices through the perforated pipes 22. If. an abundant supply of water is available, all of the valves 35 will be left open at all times and the main valve, Which admits water to the conduit 30, is opened and all of the spray pipes are thus brought into action simultaneously, with the result that the solid matteiI adhering to the filter devices is removed, and the mixture of water and unfilterable matter runs out of the chamber of its own gravity, through the opening 26 and out' through the hopper 16` and the valve 1S into the launder 19. After the spray pipes have been in action for a few moments it is advisable to assist the cleansing of the filterl devices by applying a fluid under pressure to the interior of the filter devices. To accomplish this end a moderate pressure, preferably of water, is maintained within the conduit 28 by turning the threeway valve 33, the pressure in this conduit is brought to bear upon the interior of the filtering medium. This pressure disten'ds the filter bags and immediately dislodges any residue that may remain thereon, and furthermore, especially if the fluid used is water, it passes outwardly through the pores of the filter canvas and has a tendency to free the pores of any minute particles of solid matter that may have lodged therein that would have a tendency to retard filtration. The residues having thus been discharged from the chamber of the Alter, the valves are suitabl arranged and the machine is again ready for another cycle of operations.

Method No. v2: In this method of discharging, the spray pipes are not used, but before commencing to discharge, the valve 18 is opened and the valve 24 on the pipe 23, which carries water under a high pressure, is caused to project a swift stream of water through the nozzle 25. The arrangement of these nozzles is purely a matter of design. One large one may be used, or a plurality of small ones arranged to distribute the current of water to the best advantage. This swiftly moving cu`rrent of water being started, all that is necessary to discharge the cakes of residue, is for theoperator to manipulate the three-way valves 33. During this operation, a partial vacuum is maintained in the conduit 29, while a liquid,

wvapor or gas under pressure is maintained in the conduit 28. All of the three way valves 33 at the commencement of the operation are in such a position that the vacuum is holding the cakes in position. The valves are then turned one at a time, so as to bring the pressure in conduit 2S 'in connection with the interior of the filter devices, and the result is that the cakes from each frame drop almost instantaneously when pressure is applied within the filter devices, into the space 26, and are swept away by the-current of liquid from the nozzle 25, which carries- Having thus described my invention, what I claim is: l

1. In a pressure filter comprising a chamber built up of a plurality of sections held t'ogetlier, filter devices in the upper portion of said chamber and an open passageway below the filter devices, means of projecting a stream of liquid through the passageway to carry awa residual matter caused to fall from said filter devices into said passageway.

2. In a sectional pressure filter comprising a filtering chamber, filtering 'devices in the upper portion of said chamber, an open space within said chamber communicating uy ith the filter devices', means of projecting a plurality of jets of liquid upon the filter devices, ata point near the top thereof, means of draining the mixture of liquid and residuum from said open space.

3. In a pressure filter comprising afiltering chamber composed of a series of hollow sections clamped together, filtering means in the upper portion of said chamber, a space below said filtering means adapted to receive uiifilterable matter caused to fall from said filtering means, means of cleaning the space below said filtering means by -tlic passage of a streanrof liquid therethrough.

4. ln a pressure filter comprising a filtering chamber built up of a series of sections clamped together u'ith water tight joints between said sections, a plurality of filter devices within each section, 4means of washing the exterior of said filter devices by projecting a series of jets of liquid thereon.

5. In a pressure filter comprising a filtering chamber built up of a series of sections clamped together with water tight joints betweensaid sections, a plurality of detachable filter devices within each section, means of' washing said filter devices by 'projecting a series of jets of liquid thereon, and means of conducting the mixture o1" washing liquid and residuum therefrom.

6. In a pressure filter comprising a series of frames clamped together' to form a filtering chamber, detachable filter devices in the upper portion of said frames, said filter devices being in an approximately vertical position while the longitudinal axisof the filtering chamber slopes toward a' discharge opening at the lower end thereof.

7. In a pressure filter, a main body built each section, said passageways alining to form a continuous conduit when in place,` filtering means withni said body, a chamber( within the body below the filtering means adapted to form a receptacle for material falling from the lter devices, means of' flushing said chamber by a liquid under pressure.

8. In a sectional pressure filter comprising a filtering chamber, filter devices in the upper part of said chamber, suitable means of projecting a spray of' liquid upon said filter devices, a channel adapted to drain the mixf strengthening rib formed upon its outer surface, said rib being of increased cross secture of liquid and unfilterable matter falling from the filter devices.

9. In a filter comprisingr a chamber built up of a plurality ol' sections with filter devices therein, means, of removing unfilterable mattei' from the filter devices by admittingv a fiuid under pressure with'm the filter devices and suitable means of' washing away the uiifilterablc material by a stream of liquid below the filter devices.

10. In a filter, a sectional filtering chainber, a plurality of filter devices Within said chamber, said filter dvicesiicomprising an inner corrugated member inclosed'within a filtering fabri/c, anopen unobstructed passageway within said chamber in communication with said filter devices, means of pro jecting a plurality of jets of liquid upon said filter devices at a lpoint near the top thereof, means of draining the liquid so projected from the bottom of said filtering chamber.

l1. In a filter, a sectional filtering chamber i with a plurality of filter devices in the upper portion thereof, said filter devices comprising an outer covering of a woven fabric, an open unobstructed passageway within said chamber in communication with said filter devices, means of' projecting a plurality of ljets of liquid upon said filter devices at a point near the top thereof, means of' draining the li uid so projected, from the bottom of said tering chamber.

12. In a pressure filter comprising a series of sections clam ed together'to form a filtering chamber, fi tering means in the upper portion of said chamber, a space between the filtering means and the lower walls of said chamber, a drainage opening communicating with the said space.`

13. In a frame for pressure filters having an inner member provided with two plane parallel surfaces, a web cast integral with said inner member and a bulb about the outer edges of said web cast integral thereto.

14. In a frame for pressure filters having an inner member providedwith two parallel surfaces, a gasket groove in one of the surfaces, a web cast integral with said' inner member and a bulb about the outer edges of said web cast integral thereto.

15. In a frame for pressure filters wherein a web is' cast upon said frame, and a bulb is cast upon the vouter edge of said web.

16. In a frame for pressure filters provided lwitha plate of metal formed about its periphery, and a strengthening rib formed upon the outer edge of said plate.

17. In a frame for pressure filters compris- .ing an inner wall, a web with a bulb upon its outer edges cast integral to said fr ame, and a hollow conduit cast u-pon said frame adapted to form a longitudinal passageway through said filter when the frames are clamped together.

18. In a frame for pressure filters having a tional area upon that side of the neutral axis which is subjected to tension when pressure is applied to the interioiyof the frame.

19. In a frame for pressure filters providedl with means ofprojecting a series of jets within said` frame, -eachframe being provided with a suitable valve whereby vthe ljets may be turned on or off at will.

20. In a frame for pressure filters provided f between said passageway and the main opening of the frame, means of opening and closing the duct at will.

22. In aframe for pressure filters, having filtering means in the upper portion' thereof and an open space between the inner walls of' the fi'ame and the'filtering means.

23. In a unit for pressure filters comprising an open frame, with a plurality of `openings at the top thereof for the entrance of a cleansing medium. L

24.- In a unit for pressure filters comprising an open frame, with a plurality of openings at the top thereof for the entrance of a cleansing medium, and a valve on each unit to control the entrance of liquid through the o p enings.

25. In a unit for pressure filters comprising a frame with a plurality of tubular filter de'- vices suitably supported within said frame.

26. In a unit for pressure lters comprising a frame with a plurality of tubular filter devices therein, means of removing unfilterable matter from said filter devices by a plurality of jets of cleansing medium applied to the exterior thereof.

` 27. In a frame for pressure filters having, v

for pressure filters 4having ing medium.

29. In a frame for pressure filters having filtering means in the upper portion thereof and an unoccupied space below said filtering means, means of projecting a plurality of jets upon the filtering means from a' device'near the top of the frame.

30. In a frame for pressure filters having filtering means carried by said frame, means of projecting a cleansing medium upon the filtering means, and a valve carried by each frame adapted to control the fiow of cleans- 31. In a frame for pressure filters, a conduit through said frame for draina .e of filtered liquid, a assageway throng which the filtered liquid) may enter the conduit and means of closing and opening-the passageway leading to the conduit.

32. In a frame for pressure filters, ajplurality of conduits through said frame, means of conducting the filtrate from the interior of the frame into any desired conduit, or conductin a liquid from any desired conduit into t e interior of the frame as may be desired.

33. In a frame for ressure filters, a passageway through the ame parallel with the main opening of saidf rame, a pipe connection forming communication between the passageway and the main opening of the frame and a valve on said pipe.

34. In a section for pressure filters, a pipe connection between the interior of said section and a passageway therein and a valve upon said pipe connection.

35. In a section for pressure filters, a pipe connection betlveen the interior of said section and a passageway therein, a controllable opening in said pipe connection throughl which samples of the filtered liquid may be taken when desired.

36. In a frame for pressure filters, having a rectangular upper portion and a V-shaped lower portion, detachable filtering means within said frame.

37. In a frame for pressure filters, having a square u per portion and a V-shaped lower portion, etachable filtering means within said frame.

38. In a pressure filter comprising a series of sections clamped together and sealed at the joints, filtering means in the upper portion of said sections, and an open space within the` body of the filter in communication with the filter devices int-o which residual matter may fall from. the filter devices, means of sluicing residual matter from said open s ace.

y39. n a forated device in the upper ortion thereof whereby a series of streams of liquid may be projected upon a ltering surface adjacent thereto.

40. In a frame for pressure filters, a pipe attached to the interior thereof, an'opening in said pipe through which a fluid may be projected upon a filtering surface adjacent thereto.

41. In a frame for pressure filters, a pipe attached to the interior thereof', a plurality of openings in said pipe through which a fiuid may be projected upon a filtering surface ad'acent thereto.

42. n a filter, a filterin chamber formed by a plurality of sections eld together, filtering means within the chamber, a space below the filterin means, means of cleaning said space by flusiinflr with a li uid.

43. In a filter, a filter body ormed by a plurality of sections held together, filtering means supported within the body, a space within the body below the filtering means, an inlet opening communicating with said space through which a cleansing fluid may beprojected into the space.

44. The combination of a filterframe having a conduit through one of the walls thereof and a passageway between the conduit and the interior of the frame, with a filter device secured within the frame having communication with the conduit.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 23rd day of January, 1909.

ERNEST J. SWEETLAND LUTE S. ALTER,

GRACE H. BLAIR.

framefor pressure lters, a per-v 

